A wave of summer street robberies and assaults has prompted San Francisco police to create undercover enforcement teams across the city and officers have already netted six suspects in the hard-hit Mission District area, authorities said Wednesday.

San Francisco Assistant Chief Jeff Godown said a recent string of robberies prompted him last week to order each station to create a team to catch robbers in their districts.

"Each district is conducting operations and each of them have a plan," Godown said. "There is not a specific, 'You have to do it this way' kind of plan."

He said the city typically has 10 robberies a day and the idea is to reduce the number of people being victimized.

Wednesday morning, Mission Station's street robbery abatement team - a newly formed unit of patrol and undercover officers - arrested four suspects in two robberies. Mission Station's jurisdiction, which stretches from east of Twin Peaks to Highway 101, and south of Market Street to Cesar Chavez Street, has been hit by nearly 100 robberies in the past three months.

Mission Capt. Greg Corrales said the four suspects were nabbed after police were summoned to a report of a "rat pack" attack on a victim at 14th and Stevenson streets.

The victim was walking home at 1:50 a.m. and four suspects surrounded him, the captain said.

The men beat the victim and escaped with $200 cash, his cell phone, his wallet and identification. They also took his Chicago Cubs baseball cap, only to return it to the victim.

Another victim of the robbers flagged down responding officers and recounted what happened to him, Corrales said.

The second victim told police he wandered into the area of the first robbery, Corrales said, and one of the suspects shouted, "I see another victim." He was then put in a headlock and robbed. While still in a headlock, one suspect said, "Hey, watch this!" and proceeded to punch the victim in the face.

"It was just totally gratuitous," Corrales said.

The undercover team, now alerted to both crimes, fanned out looking for suspects matching the robbers' description and found two of the men ducking behind cars near the crime scene. Officers soon caught the other two suspects hiding in bushes at a nearby park.

"They were all identified by the victims and one of the suspects had one of the victims' cell phone" and about $200 cash, Corrales said.

Arrested were Hummad McCullen, 20, of Oakland; Joseph Miles Jr., 20, of Berkeley; Eddie Olmos, 22, of Daly City and Brandon Long, 21, of Los Angeles. McCullen, Miles and Olmos face robbery charges while Long was picked up on a warrant out of Los Angeles.

On Saturday, the same Mission Station detail patrolling the Dolores Park area arrested two men on suspicion of attempted robbery and conspiracy after they allegedly tried to rob a victim in Dolores Park at knifepoint at 1 a.m.

Police recovered two knives and an iPhone taken from a purse the day before in the Financial District. Arrested were Yoxis Turcois, 19, and Roberto Rivera, 18, both of San Francisco, police said.

With the first six arrests, Godown said, the plan is to evaluate what worked with an eye to set up the best strategies in the field.

"We are going to take all these suspects and we can see whether we can clear other street robberies," Godown said.